This invention relates, generally, to a wave soldering machine which is used to solder electrical components to a printed circuit board as the circuit board is moved through a wave of molten solder, and particularly, this invention relates to a mask which is used with such a wave soldering machine.
During the manufacture of printed circuit boards, for example, electrical components are placed, generally, on such a board with the associated conductor leads of the components passing through "plated through" holes within the printed circuit board. The leads which are passed through the holes are clipped to a short length, and the printed circuit board is inserted in a wave soldering machine for soldering.
The wave soldering machine includes a soldering station and a transport mechanism for moving the circuit board to be soldered from the entrance to the machine to the soldering station therein. Flux applicators and heaters are directed at the circuit board to prepare it for soldering as it is moved towards the soldering station.
The soldering is effected at the soldering station by moving the underside of the circuit board (with the clipped leads slightly extending) through a wave of molten solder. The "wave" is like water pouring over a waterfall. Thereafter, the soldered circuit board is removed from the machine.
For certain applications, it is desirable to have certain elements of the printed circuit board remain free of solder as the board is moved through the wave of molten solder. One prior-art way of accomplishing this is to tape the elements to remain solder-free prior to placing the printed circuit board into the machine. Elements like the gold, plug-in contacts on a printed circuit board, for example, are taped to remain solder-free. This method is time consuming in both applying and removing the tape, and in addition, the tape itself is expensive.